Our ID Notes may contain important tips necessary for distinguishing this gall from similar galls and/or important information about the taxonomic status of this gall inducer.
Plant Galls of the Western United States
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Pemphigus sp. B
Midrib-gall aphid
[Page 64]
Hosts: Populus fremontii
This aphid induces large, globular galls that protrude from the ventral midrib of Fremont cottonwood leaves.
Unless noted otherwise in the ID Notes, observations of this gall are collected in the Observation Field Gallformers Code with value p-fremontii-midrib-gall on iNaturalist. You can view them here: